On the Up with OneUp

Do you have trouble getting up?

Do you suffer from a lack of stamina?

Do you have pale, skinny legs and a 1x10 drivetrain?

Does your significant other with XO1/XX1 point and laugh at your diminutive 36t cog?

If you answered yes to any of the above questions, here's your $90 solution.

What comes in the bag: 40t, 16t, spacer, and sticker
Since mid-winter there have been a couple of solutions for riders wanting a larger range cassette without the cost of going to Sram's 11speed system. OneUp Components was the first to introduce a 42t hack for 1x10 users and Wolf Tooth shortly followed. As a huge fan of 1x setups and keeping, or even increasing, my current high range while also adding a lower climbing gear with a fraction of the cost? Sign me up!

I tired out a 42t cog at first. I really liked the low gear and put a good number of miles on it, but there were some downsides. First, my XT derailleur was pretty well maxed out on B tension. This significantly slowed shifting in the higher gears and I had a few slips of the chain when really laying on the pedals. (I've heard Sram X9/X0 is better for the 42t hack) Second, you've got to drop a lesser cog to create space for the larger cog. Typically, you're going to drop the 17t or maybe 15t. This gives you a pretty good gap in gearing and overall cog size with 13-15-19 or 13-17-19. I tried with both the 15 and 17 out. Shifting sucked. In addition, the change in gearing was too large. It'd be too high or too low to remain efficient. I tried placing a 16t cog from a road cassette in place of the 17 and 15. Shifting was even worse.

I went back and forth, taking the cog off and putting it back on again. The gear was great, the overall performance was not. I was bummed. I was looking for things in my closet to sell so I could just go 11speed.

Then OneUp popped out the 40t. Followed shortly by a correctly ramped 16t cog. Hope returned. I stopped setting up my yard sale. I placed an order.

The removed 17&15t cogs
I took off the 17t, 15t, and a cog spacer. On went the OneUp spacer, 40t, 16t.

Words to live by

Setup for the 40t doesn't require the use of a longer B limit screw like the 42t did. There is even quite a few threads still showing. Chain wrap on my 11t cog losses one tooth of engagement. So far everything is looking good. Time for a ride.

Having now put ~200miles on my 40/16t setup, I'm confident in saying it is a huge improvement over my previous 42t. All my gripes with the 42t setup are cured by the 40/16 combo.

Shifting up and down the ENTIRE cassette is much more smooth. There is still a tiny bit of hesitation going up 13-16-19 if you are trying to make the shift under a high load, but it is far superior to the 15-19 jump. The change in cadence from 19-16-13 is much better, as well. Having ridden 40miles on the road in training and to/from the trails, I can say the gearing jumps are only noticeable on the road. Once on the trail, it's a non-issue.

I haven't had any problems with chain slippage, even when pushing out 1000+ watts.

I've not had one instance of the chain dropping down the cassette while back pedaling.


A 42t is a noticeably lower gear than the 40t, but 40t is still much better than 36t. My current 36 ring/40t is lower than the 34 ring/36t I had previously.

Shifting isn't as good as stock, but it is more than acceptable. Even for racing use.

That's really about it for any issues.

Bottom line?

OneUp Component's 40/16 combo is awesome. I'll be happily using it to save energy on races from Colorado to Whislter, BC.

Race ready


  1. Thanks for the review. I am currently considering a 40 or 42 for my new XT drivetrain. Being that I am coming from a SS, I am sure with a 30t nw up front, a 40t will be more than enough.

  2. I'd agree. You'll have quite a bit more gearing than before. I've been using XO1 with the 42t over the fall and the difference between a 40 and 42 isn't worth the trade off in shifting (haven't used the RAD cage which should help with that)


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